Study Reveals That Eating 'In Moderation' Is A Fool's Errand

"Moderation" is such a meaningless nutritional concept that it could actually hurt people trying to lose or maintain weight.

"Everything in moderation" is a common piece of healthy eating advice from slim and sexy celebs, dietitians and other lifestyle gurus. It's a call that's thousands of years old: The ancient Greek poet Hesiod wrote the phrase “moderation is best in all things” in his poem Work and Days, written around 700 BCE, and other philosophers and writers have echoed the maxim ever since.

But just because it’s a saying that has persisted throughout history doesn’t mean it’s right, helpful or useful.

While it sounds like wise advice for anyone who wants a low-key approach to healthy eating, the term is problematic because “moderation” is left up to each individual to define for themselves. This meaninglessness could harm people who are trying to maintain or lose weight, according to new research from scientists at the University of Georgia and Duke University.

Without a firm portion suggestion, like the government’s definition of "moderate" drinking for women as one drink a day, a "moderate" serving of something becomes a completely squishy concept that depends on a person’s eating habits and dietary preference. As a result, it can be co-opted by food companies to communicate skewed nutritional advice.

What's more, the concept plays a psychological trick on the dieter. It turns out that the more you like a food, the bigger your definition of a “moderate” serving will be, explained lead study author Michelle vanDellen, a self-regulation and self-control researcher at the University of Georgia.

"The more you like a food, the more of it you think you can eat 'in moderation,'" she said in a statement.

So what should you do instead?

While VanDellen didn't dismiss the concept of "moderation" outright, she did express skepticism about the contemporary backlash against dieting. Since we're not good at estimating portion size or estimating how much we actually eat, she said following explicit guidelines may actually help -- especially if a person wants to continue eating "in moderation."

"I strongly suspect that willingness to hold oneself accountable (for the long haul) in some form or fashion might allow someone to follow either a diet or the ‘eat in moderation’ advice," vanDellen wrote.

Other researchers who have studied moderation and weight gain are even more doubtful about the maxim's ability to help people get healthier. A 2015 study of nearly 7,000 people found that eating a broad and diverse array of foods was linked to weight gain — a 120 percent increase in waist circumference, on average, after five years. On the other hand, study participants who ate a limited amount of mostly healthy foods had the best outcomes.

These researchers noted that the results "do not support the notion that ‘eating everything in moderation’ leads to greater diet quality or better metabolic health."

People are really bad at estimating portions

Three different experiments in the new study involved a mix of 504 in-person participants and online respondents. They revealed that most people think the concept of "moderation" is larger than what a person should eat, but the size of a "moderate" portion is highly dependent on how much someone likes the food and how much of it they eat in their everyday life.

In other words, a “moderate” serving size tended to be whatever a person was already eating or drinking. This suggests that, compared to other messages about food, the concept of “moderation” isn’t an effective way to limit what people will eat.

All three experiments were theoretical in nature, in that the researchers didn’t observe people actually eating anything. VanDellen wrote that future research could pose these same questions but also evaluate actual eating habits and a person's relationship to moderate consumption. But despite this and other limitations, she still argued that the totality of the findings show that moderation is a highly individualized concept that isn’t likely to reduce consumption in any meaningful way.

Why this matters in the fight against obesity

VanDellen’s research makes the case that “moderation” should not count as a prevention tool in the fight against weight gain and obesity. Some weight loss authorities, like those behind the diet and activity tracker MyFitnessPal, have promoted the "moderation" concept to fight back against the notion that there are "good" and "bad" foods. Others, like Mother Jones journalist Kevin Drum, have settled on the moderation concept in the face of confusing and contradictory scientific research about nutrition.

Obesity continues to be a serious health issue in the U.S. Recent studies published this week in the journal JAMA confirm that obesity rates are continuing to increase for women and teens in general. In all, 35 percent of men and 40 percent of women are obese, and 17 percent of young people ages two to 19 are obese. Being obese puts a person more at risk for coronary heart disease, high blood pressure, stroke, type 2 diabetes, cancer, infertility and metabolic syndrome.

“The results highlight that part of the reason moderation messages are so appealing -- their simplicity -- is part of the problem,” vanDellen concluded. “People are poor judges of moderate consumption."

Some food companies also use 'moderation' to their advantage

The inherent squishiness of the concept makes “moderation” exceptionally useful for the junk food and fast food companies competing for space in your stomach. VanDellen’s study notes that the Chick-fil-A to-go bag is printed with this handy piece of “advice”:

Moderation is Key: All foods can fit within a healthy diet if consumed in moderation. With appropriate portion sizes and physical activity, you can enjoy treats like our Frosted Lemonade.

Indeed, 19th century playwright Oscar Wilde’s take on this ancient wisdom reveals its inherent folly: “Everything in moderation, including moderation.” In other words, moderation is for whatever you want, when you want it.